1. Field of the Invention
The present invention relates to a junction box assembly including a separate shroud configured for attachment to a printed circuit board, and including a connector opening which receives a shroud attachment bolt and a connector bolt.
2. Background Art
Vehicle junction boxes may be located at a variety of positions within a vehicle, and typically include an injection molded plastic junction box housing having a pair of printed circuit boards enclosed therein. A fuse board is exposed on one side of the junction box housing for access by a vehicle occupant or service technician. On an opposing side of the junction box housing, a plurality of pockets are formed for receiving electrical connectors, such as bolt-driven electrical connectors. These pockets are formed as part of the junction box housing, and include sidewalls and a pocket bottom. An array of holes are formed through the pocket bottom to receive a corresponding array of connector blades which protrude from one of the printed circuit boards. Accordingly, the connector blades extend into the interior of the pocket for mating engagement with a bolt-driven electrical connector when the bolt-driven electrical connector is inserted into the pocket.
In the center of each pocket, a plastic bolt opening is formed to receive a single connector bolt which attaches the bolt-driven electrical connector to the junction box housing. Also, there is typically a 2-3 mm gap between the pocket bottom and the printed circuit board from which the connector blades extend.
A problem with this design is that when the connector bolt is inserted through the connector, and torqued down into the threaded opening in the junction box housing, the pocket bottom tends to flex upwardly, and the printed circuit board from which the connector blades extend tends to flex downwardly. This flexing is caused by insertion forces of the connector acting on the connector blades, which bows the printed circuit board downwardly while the torqueing of the connector bolt pulls the pocket bottom upwardly.
Accordingly, if viewed in a vertical cross section, the pocket bottom would bow upwardly in a concave manner, and the adjacent printed circuit board would bow downwardly in a concave manner such that the gap between the printed circuit board and the pocket bottom is greater near the center of the pocket than near the periphery of the pocket. This behavior necessitates highly restrictive tolerancing for the junction box housing, openings, printed circuit board and connector blades.
This design also causes blade alignment problems which may result in reduced integrity of engagement between the wire harness connector female terminals and the PCB male blades, due to distortion of mating forces. In other words, the connector blades may not properly engage with the corresponding female mating components within the connector because the connector blades are positioned at an angle due to the bending of the printed circuit board.
Another problem with this design is that the threaded opening in the junction box housing pocket for receiving the connector bolt is plated, and when the connector bolt is torqued into this plated opening, metal shavings may drop down onto the printed circuit boards, which could potentially cause shorts.
The present invention overcomes the above-referenced shortcomings of prior art junction box assemblies by providing a junction box housing having at least one opening formed therein to receive a connector shroud. The connector shroud forms a pocket to receive a connector. The bottom wall of the pocket is attached to a printed circuit board. The bottom wall of the pocket also includes an upstanding threaded connector opening which receives a shroud bolt for attaching the printed circuit to the bottom wall of the shroud pocket, and also receives a connector bolt for attaching the connector into the shroud pocket. Accordingly, because the shroud bolt maintains the distance between the printed circuit board and the bottom wall, there is no relative gap movement and no bowing between the two when the connector bolt is torqued down, thereby eliminating the tolerancing problems discussed above.
More specifically, the present invention provides a junction box housing including at least one opening formed therein. A plastic shroud is positioned within the opening. The shroud forms a pocket having sidewalls and a bottom wall. An upstanding threaded connector opening extends upwardly from the bottom wall. The shroud pocket bottom wall is attached to a printed circuit board by a shroud bolt which extends into the upstanding threaded connector opening. Connector blades extend from the printed circuit board through holes in the shroud pocket bottom wall, and into the pocket formed by the shroud. A connector is attached to the shroud by a connector bolt which is threadedly engaged with the upstanding threaded connector opening.
Accordingly, an object of the invention is to provide an improved junction box assembly in which a printed circuit board is attached in a non-flexed configured to ease tolerancing requirements for various components of the assembly and to improve blade alignment problems between the connector blades and the electrical connector.
Another object of the invention is to prevent metal shavings from dropping onto the printed circuit boards when a connector bolt is torqued into a plated connector opening.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.